How it is diagnosed

There are specific guidelines issued by the National Institute for Health and Care Excellence (NICE) about the diagnosis and management of CFS.

NICE says a diagnosis of CFS should be considered if you meet specific criteria regarding your fatigue – for example, it can't be explained by other conditions – and if you also have other symptoms, such as sleeping problems or problems thinking and concentrating.

The diagnosis can then be confirmed if these symptoms are experienced for several months.

Most people with CFS improve over time, although some people don't make a full recovery. It's also likely there will be periods when symptoms get better or worse. Children and young people with CFS are more likely to recover fully.

Different terms for the condition

chronic fatigue syndrome – often used and preferred by doctors as there's little evidence of brain and spinal cord inflammation, which the term ME suggests; ME is also thought to be too specific to cover all the symptoms of the condition

myalgic encephalomyelitis (ME) – preferred by those who feel CFS is not specific enough and doesn't reflect the severity and different types of fatigue, and implies that fatigue is the only symptom (myalgic encephalopathy is sometimes also used)

systemic exertion intolerance disease (SEID) – a new term suggested in a 2015 report by the US Institute of Medicine, which implies that the condition affects many systems in the body (systemic); the word "disease" highlights the serious nature of the condition in some people